1. Field of the Invention
The invention relates generally to bulk material dispensers, and more particularly to dispensers for particulate material such as salt, sand and the like.
2. Reference to Prior Art
Broadcast spreaders or dispensers are commonly used for spreading metered amounts of particulate material. A known broadcast dispenser includes a hopper that holds the particulate material and that funnels that material down to a discharge spout. From the discharge spout the material pours onto a rotating broadcast apparatus to be cast over a desired surface.
To encourage free flow of material out of the discharge spout and to prevent blockages in the hopper due to material agglomeration or "bridging", it is known to provide the hopper with an agitator. As used herein, "bridging" means that particulate material forms a blockage or bridge extending between opposite sides of the hopper, such that a space beneath the blockage is empty. The agitator is positioned within the hopper and typically includes a rotating shaft and agitating members secured to the shaft so that they mix the material as the shaft rotates. Known agitator members include, for example, an auger arrangement (U.S. Pat. No. 3,948,421 issued Apr. 6, 1976) or chains that are thrown outwardly by the centrifugal force generated by the shaft (U.S. Pat. No. 3,223,290 issued Dec. 14, 1965).
In one application, broadcast dispensers are used to spread salt or sand over surfaces such as roadways and walkways. Examples of such dispensers are provided in U.S. Pat. No. 3,819,120 issued Jun. 25, 1974 and U.S. Pat. No. 3,559,894 issued Feb. 2, 1971. Both of those patents illustrate dispensers mounted on vehicles, such as on the back of a pick-up truck.